Pneumatic tire



Patented Sept. 27,1898# PNEUHTIU TIRE. (Application mad .nuts `1.1.5, 189s.)l

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i SPECIFIGTON forming part of Letters Patent No. 611,594, dated September W7, 189B,

pplication filed June 15,1898. Serial No. 683,483. lNQ nmdel.)

To all whom it may concern;

Be it known that l, Erfassen KEMPsnALL, ol' Newton, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements 'in Pneumatic Tires, of which the following is a specification.

This invention relates to a pnenmatic'tire which is provided at' its treadsunface with a cushion of spongerubbor or other suitable material to protect the air-tube of. the tire againstpuncturing means liable to be encountered and to increase the resiliency of the tire.

The invention 'has forits object to provide an additional safeguard against puncturing of the air-tube in case the puncturing projection orolxject succeeds in penctrati-ngtbo protecting-cushion.

The invention consists in the im proveniente -which I will now proceed to describe and claim. i

Of thc accompanying drawings, forming a part of this specification, Figure l represents a cross-section of apneumatic tire embodying my invention. Figs. 2 and represent cross-sections, showing' the tire atdierent stages of its formation.

The same letters of reference indicate the saine parts in all the figures.

ln the drawings, a represents the inner air-tube, which is composed of rubber and is made by forming an unvulcanized rubber tube upon a rod or mandrel. Before the tube is vulcanized I apply to its outer portion a strip b of any material which is impervious to air, or, in other Words, which in the event of the formation of a puncture. through thesaid strip b and the air-tube will not permit the air escaping from the tube tovvork its way along the width of said strip. ylt isa fact that the strip b, if made of certain ma-` terials ordinarily employed in the manufactureof pneumatic tires-for instance, ordinary textile fabric with or without a coating of rubber-Would permit air that may escape through a puncture'made in the air-tube ci and in the said strip to filter, as it were, along the strip and work its way along the tire until it found a means of escape.

My invention is based upon the discovery that by using a strip b of some material'which will not permit air to pass through vor along i it in any direction I can prevent lossV of air from a puiictured air-tube when a cushion c 55 of sponge-x-ubber-is -placed upon-the outer side of the-strip '5. To this end the strip, b

may be made of non-extensible material, such as manila paper, glazed 1n uslin, &c. After a strip l) has been placed upon` theV airftube, oo

as shown in Fig. 2, the spongelrubber cushion c, 'which Vhas already been partially vulcanized and rendered spongy, is placed upon the outer surface or" the strip b, as shown in Fig. 3, and the whole isthen incloscd ina 65 suitable Wrappercomposed of one or more layers of frictioned fabric, such asis ordina# rily used in the manufacture of pneumatic l ha ve here-shown two tayersmnaneiy,

an inner layer rl and an outer layer (Z-the"7o inner layer bearing' upon the air-tube a and l upon the outer surface of the cushion c.l Upon the outerlayer d l forni an external coating c of unvulcanized rubber. v The tire is then subjected to vulcanization and corn- 7 5 pleted in the usual manner. Inj the coinpleted tire the air-tube adheres closelyto the air-proof strip b', and is thereby rendered nonextensible toward the sponge-rubbeigrand in the event of the penetration of the cush- 8o ion and the strip b into the air-tube by a penetrating instruinentthe air that escapes through the perforation cannot worin its way through the unperforated material of the strip l) and toward the edges of' the latter owing`85 to the nature-of the strip and can only pass through the perforation into 4the cushion c, Wbichremains in its normaluncompressed yielding condition: Owing to the cellular nature of the cushion the perforation Inade 9o in it is closed by the 'expansion of the W'alls of the cellsof the cushion, so that there is no objectionable escape of air from the tube throughthe cushion and owing to the nonextensible strip 1J thesaid cellular lnature of 95 the sponge-rubber cushion Vis not materially altered either by the pressure of 'air confined in the tube o,v or bythe slight amount of air that may escape'through a puncture into a few of the cells.

' 1 claim- IOO `A A pneumatic tire comprising an air-tube, a

sponge-rubber cushion, n suitable covering In testimony whereof Il'mve a'xed my sig-1 for the saidtube and cushion, and a strip of nature in presence of two witnesses.

non-extensible air-jjroof material interposed 1 r between the cushionV and air-tube and adapt- RLRAMR KEMFSHALL' 5 ed to prevent the compression of the cells of Witnesses:

the 'cushion by @he pressure of nir in the A. D. HARRISON,

tube. v v P. W.- PEZ'ZETTI. 

